Canine histiocytic sarcoma presenting as a target lesion on brain magnetic resonance imaging and as a solitary pulmonary mass.

Author Information: Department of Veterinary Surgery and Radiology, University of California Davis School of Veterinary Medicine, Davis, CA, 95616.; Small Animal Medicine and Surgery, University of Georgia, Athens, GA, 30602.; Diagnostic Imaging, University of Georgia, Athens, GA, 30602.; Department of Pathology, University of Georgia, Athens, GA, 30602.; Department of Pathology, University of Georgia, Athens, GA, 30602.

Abstract

A 6-year-old spayed female miniature schnauzer presented with generalized seizures and progressive multifocal intracranial neurologic disease. Thoracic radiographs and computed tomography (CT) revealed a large solitary pulmonary mass within the right cranial lung lobe. On brain magnetic resonance imaging (MRI), a solitary intraparenchymal mass within the left piriform lobe had a "target" appearance on both pre- and postcontrast sequences. Cerebrospinal fluid was unremarkable and histopathology indicated both masses represented histiocytic sarcoma. This case represents an uncommonly reported MRI appearance of histiocytic sarcoma in the canine brain and a large, solitary-appearing pulmonary histiocytic sarcoma in the same dog.